One great article of manufacture and export, however, down to this period, continued to be that of our woollens. To guard this manufacture many Acts had been passed at different times, prohibiting the exportation of the raw material. Immediately after the Revolution a fresh Act of this kind was passed, and such was the jealousy even of the Irish and of our American colonies weaving woollen cloths, that, in 1689, an Act was passed prohibiting the exportation of wool or woollen goods from Ireland or our plantations to any country except England. Having taken measures thus to confine as much as possible the profit of the woollen manufacture to England, the next year, which saw all protecting duties taken off corn, saw also leave given for the exportation of woollen cloths duty-free from England to any part of the world. Sir William Davenant estimates the value of the yearly growth of wool in England at this time at about £2,000,000, and the value of its woollen manufactures at £8,000,000. He calculates that one-fourth of this amount was exported. In 1738 Mr. John Kay invented the mode of casting the shuttle by what is called a "picking-peg," by which means the weaver was enabled to weave cloths of any width, and throw off twice the quantity in the same time. In 1758 the Leeds Cloth Hall was erected, and, about twenty years afterwards, a hall for white cloths. The silk trade received a great impulse by the erection of a silk-mill at Derby, in 1719, by John Lombe and his brothers. Lombe had smuggled himself into a silk-mill in Italy, as a destitute workman, and had then copied all the machinery. To prevent the operation of this new silk factory in England--which was worked by a water-wheel on the river Derwent, had 97,746 wheels, movements, and individual parts, and employed three hundred persons--the King of Sardinia prohibited the exportation of the raw material, and thus, for a time, checked the progress of the manufacture. Parliament voted Sir Thomas Lombe £14,000 as a compensation for loss of profits thus occasioned, on condition that the patent, which he had obtained for fourteen years, should expire, and the right to use the machinery should be thrown open to the public. By the middle of this period our silk manufactures were declared superior to those of Italy, and the tradesmen of Naples recommended their silk stockings as English ones. In 1755 great improvements were introduced by Mr. Jedediah Strutt in the stocking-loom of Lee.